Clamp rod assembly



15, 1931. B. A. BRITTAIN CLAMP ROD ASSEMBLY Filed April 22, 1929 A TTORNE Y5,

Patented Dec. 15, 1931 UNITED STATES BUIN'A A. BRI'I'I'AIN, 01 LOS ANGELES, CALIFORNIA CLAMP ROD ASSEMBLY Application filed April 22,

This invention relates to a device for gripping rods and like work and is shown herein embodied in a polish rod clamp for well pumping apparatus. A common type of 011 8 well pumping apparatus comprises a reciproeating .piston, a sucker rod string embodying a polish rod and a walking beam for reciprocating the sucker rod string. Clamps are currently used to grip the polish rods and such rods are linked to-the walking-beam by means of the clamps. It is desirable to have a clamp arranged so that its longitudlnal position on the polish rod may be changed. This is commonly termed in the art spacing.

The objects of this invention are to provide a clamp having any or all of the following features: means to increase the grip upon the work in proportion to the load supported.

thereby; a clamp assembly with supportmg' arms so arranged that the weight of the assembly when supported from the arms will initiate the gripping action and wherein movement of the arms in a reverse direction will cause release of the work; and a simple compact, durable clamp assembly.

These objects together with other objects and corresponding accomplishments are ob tained by means of the embodiment of my invention illustrated in the accompanying drawings, in which Fig. 1 is a side elevation of a fragment of a pump operating structure; Fig. 2 is an enlarged plan view of the clamp assembly; Fig. 3 is a section as seen on the line 33 of Fig. 2, the arms being in work engaging position; Fig. 4 is a view similar to Fig. 3 showing the elements of the assembly in work releasing position, the view being partly in elevation; Fig. 5 is a section as seen on the line 55 of Fig. 3; and Fig. 6 is a perspective view of one of the slips.

The assembly shown herein comprises broadly a body having slips which are disposed on tapered surfaces in the body so as to grip work such as a pipe or sucker rod and to automatically vary the grip by reason of. the weight or pull of the work. Broadly this is the same construction as a spider and slips commonly used in supporting casing.

1929. Serial No. 856,995.

In addition to the body and slip construction, the present invention embodies, a means by reason of the weight of the assembly operable'to set the slips in gripping position.

Referring with more particularity to Fig. 1, A indicates a fragment of a walking beam of the usual type employed in oil wells. Supported from the walking beam is the clamp assembly indicated generally by B and en'- gaged withthe polish rod of a sucker rod lbo string C. The polish rod reciprocates through a well casing head D.

The clamp assembly comprises a body 10 split for convenience of assembly. At opposite sides of the body areslots 11, the body fi i having ears 12 projecting at the slots and V 7 serving to support pivot pins. Extending through the body is a slip opening 13 and as shown substantially rectangular in transverse section. Opposite side walls oftheo ening are preferably inclined as indicate by 14 so as to converge downwardly. Mounted in the slip openings are slips 15 having half' round openings 16 to embrace the work which in the drawing is shown as a polish rod 17." In the bearing faces of the slips are rocker arm recesses 18. A pivot pin 19 extends between each pair of ears 12 and supports a rocker arm marked 20. The arms have stubs at their ends to receive the eyes of cable 30 sockets 21. A cable 22 is secured in the sockets and passes over a saddle 23 on the walking beam. Protuberances 24 on the arms are disposed in recesses 18 forming couplings between the arms and slips. It is obvious that the clamp assembly is supported from its rocker arms 20, the weight of the assembly being such that the body 10 will tend to move downwardly due to its own weight. This downward movement causes av rocking movement ofthe arms in relation to the body and the protuberances 24 disposed in recesses 18 will tend to move the slips downwardly and cause them to embrace and hu the polish rod. It will be noted that there is a clearance between the protuberances 24 and the walls of the recesses so that the arms do not have a direct action tending to thrust the slips toward one another, contraction of the slips being due entirely to their bearings upon 15'] which is small.

the walls of the slip openings. The weight of the clamp assembly is such as to initiate the clamping engagement of the slips. Any weight of the sucker rod string will tend to cause the slips to be further contracted and the grip will be proportioned to the load. The function of the rocker arm is merely to initiate clamping action, the arms and slips constitute a leverage system, acting as an amplifier to multiplythe force on the outer ends of the arms and transmit it to the slips to produce a resultant lateral movement of relatively great magnitude to grip the rod. The only tendency to release the grip is that due to the counter acting weight of the arms To release the clamp, the suckerrod string is independently supported,

and by force applied directly to the body of the clamp assembly leaving the arms free, the body is moved downwardly so as to swing the rocker a-rms' in the reverse direction to the position shown in Fig. 4.

Itis obvious that the invention may be 1 embodied in a device for supporting other work, such as pipe, and'that the arms may besuppoi'ted by other means, such as upon a table. Various other applications of the invention will be apparent to those skilled in the art.

' What I claim is 7 1. A clamp assembly comprising a body 4:. A clamp assembly comprising a body having oppositely disposed slots with ears for-pivot pins, a slip opening in said body having inclined bearing walls, work engaging sli-psmounted in .said opening and having inclined bearing faces engaging said walls, "rocker arms, p1ns pivotally supporting said arms onsaid ears,.sa1d slips having recesses in their bearing faces, protuberances on said arms disposed In said recesses and solely bearing laterally onsaid slips to effect longitudi *nal movement of said slips whereby on rocking ofthe arms. longitudinal movement of said slips will be initiated.

In witness that I claim the foregoing I have hereunto subscribed my name this 11th day of April, 1929.

i BUNA A. BRITTAIN.

' having a slip opening, work engaging slips 'mounted therein for longitudinal movement,

said slips and said body having coacting surfaces so that longitudinal movement of said' slips in relation to said body will cause said faces, rocker arms pivotally mounted on said slips to be moved laterally to effect either gripping or release of the work, said slips having rocker arm recesses on their bearing body and having protuberances disposed in said recesses and solely bearing laterally on said slips to effect longitudinal movement of the latter whereby on rocking of the arms longitudinal movement of said slips will be l initiated.

walls, work engaging slips mounted therein .and hZLVlIlg inclined bearing faces, engaging said bearing walls so that longitudinal move- ,7 f ment of said slips in relation to said body Wlll cause said slips to be moved laterally to effect either gripping or release of the work, said' slips having recesses in their bearing faces, rocker arms pivotally mounted on said body and havingv protuberances disposed in said I initiated.

recesses and solely bearing laterally on said slips to effect longitudinal movement of said slips whereby on rocking of the arms longitudinal movement of 'said slips will be 1 3. 'A clamp assembly havingoppositely disposed slots with ears for pivot pins, a slip opening in said body comprising a body 

